1. Field of the Invention
The present invention generally relates to a semiconductor package, and more particularly to a semiconductor package having a wire bonding structure for electrical connection between bonding pads of a semiconductor chip and leads of a lead frame.
2. Description of the Related Art
In the electronic industry, integrated circuits are commonly encased within packages made of plastic or ceramic.
A ceramic integrated circuit package comprises a ceramic substrate including contact pins to connect an integrated circuit enclosed in the package to external circuitry. The package is hermetically sealed with a ceramic lid.
So as to fabricate a ceramic integrated circuit package, a number of steps for properly adhering conductive metal patterns and contact pins to the ceramic package are required. Such metal patterns and contact pins serve to provide electrical paths between external circuitry and the integrated circuit encapsulated within the ceramic package.
Typically, a metal such as tungsten is used to form metallic wire bonding areas, die attach area, and external bonding pads on the ceramic substrate.
In order to provide corrosion resistance, it is highly desirable to coat or plate wire bonding areas, die attach area, and external bonding pads with a material such as tungsten.
FIG. 1 is a perspective view of a semiconductor package according to the background art.
Referring to FIG. 1, a ceramic package has signal transfer paths from a semiconductor chip 1 to external circuits(not shown), which consist of bonding pads 1a, wires 2, inner leads 3 and outer leads 4.
So as to form the signal transfer paths, one group of terminals of respective wires 2 are connected to the corresponding inner leads 3 by soldering and the other group of terminals of wires 2 thereof are also connected to the bonding pads of the semiconductor chip 1 by soldering.
However, the inner leads 3 are put on a plane of almost the same level as the bonding pads, and the bonding wires have a convex curved shape. Therefore, when chip size becomes larger depending on the increase in the integrity, wire length increases. As a result, the semiconductor package may induce a problem that bonding wires droop. Since the drooping wires may contact with each other, their signal transfer paths may come to be in an unstable state.